1. Technical Field
The present invention relates to a brushless motor having an improved coil wire binding structure inside a slot of a stator stack.
2. Description of Related Arts
A brushless motor includes an armature where a plurality of coils is wound and a magnetic exciter having a permanent magnet. Typically, an outer rotor type brushless motor is employed in an axial flow fan such as a cooling fan. In the outer rotor type brushless motor, an armature having a coil is provided as an inner stator, and a magnetic exciter having a permanent magnet is provided as an outer rotor in an outer circumference of the stator.
The coil is housed in a plurality of slots formed in the stator stack. For example, in the case of a stator stack having twelve slots, it is necessary to route twenty four connecting wires on a three-phase basis (u-phase, v-phase, and w-phase). Therefore, a wire binding work for the connecting wire of the coil becomes cumbersome and increases a manufacturing cost.
In this regard, it is desirable to develop a technology capable of simplifying and optimizing a coil wire binding work. As a related art for a simple and efficient coil wire binding work, a technique is disclosed, in which each end portion of a plurality of stator coils is commonly connected to an electric conductor provided in an insulation cover of the stator core, so that the electric conductor is used as a connecting wire and a print pattern (for example, refer to JP 2001-327110 A).
In the technique disclosed in JP 2001-327110 A, the coil wire binding work is simplified and optimized by using the electric conductor provided in the insulation cover of the stator core as a connecting wire and a print pattern.
However, in the technique disclosed in JP 2001-327110 A, it is difficult to change a wire binding pattern of the coil without changing a coil structure or a wiring structure of the connecting wire to the electric conductor. For example, in the brushless motor having twelve slots, twenty four connecting wires are routed on a three-phase basis (u-phase, v-phase, and w-phase). However, performance of the motor rotation changes depending on a wiring pattern of the connecting wire.
Therefore, in the technique disclosed in JP 2001-327110 A, it is necessary to change the coil structure or the wiring structure to the electric conductor whenever a design of the wiring pattern of the coil changes. This further causes cumbersomeness of the coil wire binding work.